In the production of "chopped strand", continuous bundles or strands of glass fibers or filaments are severed or "chopped" to produce the discrete segments of strand. In one well-known system, the glass filaments are drawn from streams of molten glass and directly chopped into discrete segments through the action of a single attenuation-severing means. For example, see U.S. Pat. No. 4,194,896 for one such system.
Such attenuation-severing means are generally comprised of a driven cot roll which first supplies the attenuative forces to draw the streams of molten glass into filaments and, secondly, functions as a bearing surface against which the blades of the cutter roll chop the continuous glass filaments into discrete segments. Generally, the circumferential surface of the cot roll has an elastomeric layer thereon to facilitate the attenuation and severing functions.
Further, the axis of rotation of the cot roll has generally been fixed, and the axis of rotation of the cutter roll has been laterally movable so that the force with which the cutter roll bears against the elastomeric surface of the cot roll is adjustable to compensate for part wear, among other reasons.
Historically, the adjustment mechanism for the cutter roll has been a "slide" type configuration with the mating slide surfaces, unfortunately, adjacent the rapidly rotating cutter and cot rolls. In such an environment, wherein the strands are generally coated with various liquid materials, the slide surfaces tended to collect various foreign materials and/or corrode as a result of contacting such coating material. Thus, the ability to adjust the cutter roll became increasingly difficult over the life of the chopper.
Since the elastomeric layer on the cot roll is generally relatively thin, the length of adjustment provided by the slide mechanism associated with the cutter roll was relatively short, notwithstanding the fact that the slide system associated with the cutter roll was relatively large in comparison. Thus, the ranges of diameters of the cutter roll and cot rolls associated with a given chopper were severely limited.
The present invention provides a system wherein the adjustment mechanism for increasing or decreasing the space between the axis of rotation of the cutter and cot rolls is positioned outside the zone immediately adjacent the rotating cutter and cot rolls which receives the spray of coating material from such rolls, and the present invention also provides a system wherein cot rolls may be employed having substantially different diameters, as well as cutter rolls of substantially different diameters.